Effect of Leucocyte- and Platelet-Rich Fibrin on Palatal Wound Healing After Free Gingival Graft Harvesting

Soft tissue grafting techniques using autogenous free gingival grafts and connective tissue grafts are reliable and predictable procedures that are commonly used to increase the dimensions of keratinized gingiva. These tehniques are indicated in situations such as shallow vestibular depth, gingival recession, and inadequate peri-implant attached gingiva. Although free soft tissue grafts can be harvested from various intraoral sites, the keratinized gingiva of the hard palate in the premolar-molar region is the most commonly used donor site. However, harvesting tissue from the palate presents challenges for patients, including a second intraoral surgical wound and an increased risk of postoperative morbidity. The palatal wound, which typically heals over two to four weeks by secondary intention, often causes significant patient discomfort due to pain, burning sensation, prolonged bleeding, and delayed healing, often caused by secondary irritation.

Leukocyte- and platelet-rich fibrin (L-PRF), a second-generation platelet concentrate, was developed for oral and maxillofacial surgery in 2001 by Choukroun et al. Polymerization without any biochemical activation, which occurs in a manner comparable to the natural coagulation process, produces a strong fibrin matrix resistant to rapid resorption. Compressing this fibrin matrix creates a strong, suture-resistant membrane that can be fixed to the wound edges and provides a stable barrier against the oral environment.

While L-PRF has shown promise in several applications in regenerative dentistry, randomized controlled clinical trials evaluating L-PRF membrane as an adjunct for donor site wound healing in free gingival grafting procedures are limited in the literature. This study aimed to evaluate the efficacy of L-PRF membrane as a palatal wound dressing in promoting wound healing, hemostasis, and pain control at palatal donor sites following free gingival grafting procedures.

Patients requiring soft tissue augmentation with a free gingival graft due to inadequate keratinized attached gingiva were included in this study. Patients were randomized to either an L-PRF group (n=13) or a control group (n=13). All procedures were performed by a single clinician to reduce variability in surgical technique. After achieving adequate anesthesia, a recipient site was prepared to receive the graft in areas lacking sufficient attached gingiva. This procedure involved an incision at the mucogingival junction followed by blunt dissection to separate the epithelium from the underlying connective tissue, creating a vascular bed for graft integration and survival. A sterile paper template was created to match the dimensions of the recipient site. The paper template was positioned on the palatal mucosa in the premolar/molar region, and the graft margins were outlined with a scalpel. A 1-2 mm thick graft consisting of epithelium and a thin layer of connective tissue was carefully harvested by moving the blade parallel to the mucosal surface. The free gingival graft was carefully oriented on the recipient site, with the epithelium facing outward and the connective tissue in contact with the recipient bed. It was then sutured to ensure close contact between the graft and the underlying tissue to prevent any movement that could compromise revascularization and lead to graft failure. In the L-PRF group, 10 ml of venous blood was drawn from the antecubital vein of the patient using sterile, anticoagulant-free vacutainer tubes and immediately centrifuged at 3000 rpm for 10 minutes. A fibrin clot was structured in the middle of the tube, just between the red corpuscles at the bottom and the acellular plasma at the top. The L-PRF layer was isolated and compressed into a flexible membrane using its special box. The L-PRF membrane was shaped to fit the donor site wound and placed as a single layer, ensuring complete contact with the underlying tissue. It was secured at the wound corners using 5-0 bioabsorbable polyglactin sutures to minimize displacement during the healing process.

Participants were evaluated on days 1, 3, 5, and 7, and weeks 2, 3, 4, 5, and 6 postoperatively to monitor wound healing and complications at the palatal donor site. An examiner recorded subjective parameters (pain, burning sensation), clinically evaluated objective parameters (postoperative bleeding, wound healing, and color matching with the adjacent healthy tissue), obtained donor site photographs, and performed wound area measurements using digital image analysis. Blinding of patients to L-PRF treatment was not feasible due to ethical concerns regarding the collection of blood samples in the control group, and blinding of investigators during digital image analysis and clinical assessment was also not feasible due to the nature of the surgical procedures.